JPH076394B2 - Internal combustion engine with cylinder intake port - Google Patents

Description

TECHNICAL FIELD The present invention relates to internal combustion engines, and more particularly to cylinder intake ports for internal combustion engines. In particular, the present invention relates to an intake port formed in a cylinder head in such a form as to generate a vortex in the intake fresh air flowing into a corresponding combustion chamber and a port shape for obtaining a high flow rate effectively associated with a vortex flow. As used herein, "intake charge" means the fuel-air mixture drawn into the cylinder during the intake stroke of the piston in the cylinder of the engine.

BACKGROUND Many forms of cylinder intake ports, or cylinder head intake ports, have been designed and utilized to create rotation or vortices in the intake fresh air supplied to a combustion chamber or cylinder. However, in general, in the form of the intake port, that is, the intake passage that is designed to generate a considerable fresh air vortex flow, the amount of fresh air flowing to each cylinder in the intake stroke of the piston is reduced, which is called "volume reduction efficiency". The result is called. This means a reduction in fresh air amount when calculated at standard temperature and pressure.

In recent years, in order to increase the amount of fresh air vortex in a spark ignition type internal combustion engine, for example, a gasoline engine, it has been of great interest among engine designers to newly install an intake port for vortex generation. Has been proposed. These proposals include both fixed and variable intake ports, which incorporate one or more moving components to provide a high degree of swirl at low load and high load. Time (maximum fresh air is desired)
To reduce the degree of vortex flow and improve the packing volume efficiency. However, there is still a need for a simple fixed intake port that can generate a significant degree of vortex while providing high fill volume efficiency.

SUMMARY OF THE INVENTION The present invention provides a fixed cylinder intake port that can be used in an internal combustion engine to provide a cylinder fresh air vortex combined with a high degree of cylinder fill volume efficiency. This improved intake port structure does not use protruding blades, side walls, or other devices that restrict the flow of fresh intake air toward one side of the intake port, but instead uses a different downward facing along the upper wall of the intake port. It has a tilt angle and at various degrees of tangential angle directs the flow into the vortex cavity below the ledge of the intake port, thereby creating a vortex in the cavity, which in turn causes combustion of the corresponding cylinder through the throat. It has slopes that direct the flow into the chamber. Preferably, the port shape in a plane perpendicular to the valve axis provides a relatively straightforward flow rate within the swirl cavity outside the valve axis under a gentle angled slope, and
Under the steep angled slope, the inside of the valve axis provides a more offset flow path within the vortex cavity. The structure also includes a hanging valve guide with or without a leading edge fairing or guide vanes that creates laminar flow at the port, and a curved intake passage shape or a relatively straight upstream intake passage shape. It can also be applied to.

These and other features and advantages of the present invention will be more fully understood from the following description of a preferred embodiment in connection with the accompanying drawings.

DETAILED DESCRIPTION Referring now in detail to the drawings, reference numeral 10 generally indicates an internal combustion engine constructed in accordance with the present invention. The internal combustion engine 10 is
As usual, it includes a cylinder block 11 having a plurality of cylinders 12 (only one shown). One piston 14 is installed in each of the cylinders, and a connecting rod 15 connects each piston to a crank shaft (not shown) supported in the cylinder block.

A cylinder head 16 is mounted on the top wall 18 of the cylinder block to close the adjacent end 19 of the cylinder. The cylinder head includes an end wall 20, first and second side walls 22,23 and top and bottom walls 24,26, the bottom wall 26 resting on the top wall 18 of the cylinder block.

At each cylinder position, a combustion chamber depression 27 is formed in the bottom wall 26 of the cylinder head at the end 19 opposite the top of the piston 14 of each cylinder. The piston, cylinder and cylinder head, including the recess 27, form a variable volume working combustion chamber 28. Spark plug opening in the combustion chamber of the depression 27
An exhaust port 31, an exhaust port 31, and an intake port 32 formed according to the present invention are connected.

The spark plug opening 30 receives a spark plug (not shown) having a discharge gear located within the combustion chamber cavity, as is conventional.
The exhaust port 31 extends from a circular exhaust valve seat 34 and throat 35 (open to the combustion chamber) along a curved flow path to an exhaust port 36 which penetrates the second side wall 23 of the cylinder head and extends to the exhaust manifold (Fig. (Not shown).

The intake port 32 extends from a circular intake valve seat 38 and a throat portion 39 adjacent to the intake valve seat 38 to an intake port 40 penetrating the first side wall 22 of the cylinder head along a flow path which will be described later, and is connected to an intake manifold (not shown). Connecting. The poppet type intake / exhaust valves 41 and 42 shown only in FIGS. 2 and 3 are intake / exhaust ports, respectively.
It is provided at 32 and 31. The exhaust valve 42 has a circular head 43, which can be seated on the valve seat 34, by means of a valve stem 44 supported in a valve guide 46 mounted in the top wall 24 of the cylinder head. It is supported. A spring 47 and a conventional valve actuation mechanism (not shown) are provided to actuate the exhaust valve in a coordinated manner with engine crankshaft rotation.

The intake valve 41 also includes a head 48 that seats on a valve seat 38 to control the flow through the intake port 32. Valve stem 49 reciprocates from intake valve head
It extends along 50 and is reciprocally supported within a valve guide 51 mounted on the cylinder head top wall 24 in suitable guide bosses 52, 54. Similar to the exhaust valve, the intake valve 41 is an appropriate valve actuation device (not shown) according to the rotation of the engine crankshaft.
It is operated by. The valves 41, 42 operate to open and close the intake and exhaust ports in the usual manner.

According to the present invention, the shape of the intake port 32 is such that a swirl is generated in this intake fresh air without unduly limiting the maximum intake fresh air amount to each cylinder. In order to properly visualize the shape of the intake port in the cylinder head shown in FIGS. 1 to 4, the shape of the core that can be used to shape the intake port to the desired shape in FIGS. 5 to 7 Is shown. When listing the features of the structure of the port 32, the corresponding features of the core are also given the same reference numerals to clarify the relationship between these features. It should therefore be understood that the reference numerals used in FIGS. 5 to 7 showing the core actually indicate the corresponding features of the intake port formed by this core.

The port 32 extending from the inlet 40 includes a surface surrounding the passageway, which is divided into four wall surfaces including an upper wall 55, a lower wall 56 and left and right side walls 58, 59 for convenience of description. The intake port 40 has a substantially circular shape, and various top walls, bottom walls, and side walls are connected to each other by rough arc surfaces, and the intake port is formed with a simple curvature or a complicated curvature. It extends smoothly inward from 40. Therefore,
It should be understood that the separation or division lines between the walls that are connected are not clearly defined, and that different signs are used for descriptive purposes only. It should also be appreciated that the particular shape of the wall at the entrance to the port is not so important as to affect the features of the invention. However, it is desirable that the flow path of the fresh intake air sent toward the combustion chamber is smooth.

As the inlet 40 approaches the valve stem 49, the inlet top wall
55 is interrupted by a downwardly extending valve guide boss 54. The valve guide boss 54 has an upstream fairing ring (sometimes referred to as a guide vane 60) that extends upward along the center of the upper wall 55 to allow flow along the upper wall on either side of the valve guide and valve stem. Divide smoothly. The valve vane 60 includes an upstream edge 61 which is connected to the valve guide boss 54 by two faces 61a, 61b. These surfaces lie substantially parallel to the flow direction on both sides of the guide boss and are tangentially connected to the sides of the guide boss.

The presence or absence of a depending valve guide boss and guide vanes attached to its leading edge is also shown in the drawings and utilized in the preferred embodiment, but is not absolutely necessary for the concept of the invention.

Along the upper wall on both sides of the guide boss and the guide vanes 60 associated therewith, the intake port is provided with inner and outer beveled portions 62, 63 sloping downward. The outer beveled portion 62 is so called because it extends downwardly and tangentially (as viewed from above or below) along an adjacent portion of the wall of the corresponding cylinder. The inner sloped portion 63 extends along the opposite side of the valve guide boss and the guide vanes and is inclined toward the center of the combustion chamber.

An essential feature of the invention is that the angles of these two beveled portions are quite different. The inner sloped portion 63 is much steeper than the outer sloped portion 62 (10 ° or more), measured from a plane parallel to the bottom wall 26 of the cylinder head.
It is said. At their lower ends, these beveled portions 62, 63 are connected to a ledge portion 64 which extends smoothly from the end of the beveled portion at a position approximately opposite the valve guide and corresponding valve axis. . The ledge extends beyond the beveled edge in a direction generally parallel to the bottom wall 26 of the cylinder head and is spaced apart from the throat section 39 of the intake port and occupies a generally opposed position. An open hollow vortex chamber 66 is provided below the shelf at the port end around the axis of the intake valve 41. The vortex chamber 66 is substantially centered on the valve axis, and the left and right side walls converge so as to form a cylindrical shape around the valve axis, and are connected by the ends 67 of the ports. The lower part of the vortex chamber is inclined inward and connects to the throat part 39.

Due to the slight inclination of the valve axis with respect to the cylinder axis in the illustrated embodiment, the shape of the port is slightly off center from the valve axis as seen in FIG. 1 and extends further toward the outer edge rather than the center of the cylinder. Please note that there is. However, FIGS. 5-7 show that the flow areas on both sides of the valve guide boss are substantially equal to each other.

The different angled slopes of the sloped portions 62, 63 extend the length of the gently sloped outer sloped portion 62 and the steeply sloped inner sloped portion 63.
Will shorten the length of. Accordingly, these bevels intersect the shelves 64 at alternate positions on either side of the valve axis, as shown by the diagonal lines 70 in FIGS. 1, 6, and 7. This diagonal line 70 generally shows the intersection of the slope and the shelf on both sides of the valve guide boss.

As a result of this construction, the fresh intake air flow guided by the outer beveled portion 62 is guided somewhat tangentially into the vortex chamber 66 outside the valve stem, relatively far from the vortex chamber 66 of the port, and at the top of the port. A vortex is generated in a counterclockwise direction when viewed from above (clockwise when viewed from the bottom as in FIG. 1). The flow guided by the steeply angled inner beveled portion 63 is directed downwardly toward the intake port throat 39 inside the valve stem. Therefore, the steep slope of the inner sloped portion 63 not only slightly reduces the flow rate inside the port (because of the greater diversion), but also directs this flow further downward, reducing its effect on the vortices. Therefore, the overall effect of the slope is that it creates a counterclockwise vortex and provides a large, relatively resistance-free flow path on both sides of the intake valve stem and valve guide boss, when the slot is wide open. Alternatively, it is to give inhaled fresh air that is relatively unthrottled in the full load state.

Preferably, the shape of the port when viewed from a plane perpendicular to the intake valve axis or the cylinder axis shown in FIGS.
Below the less angled beveled portion 62, a relatively straightforward flow should be provided in the port from immediately upstream of the valve guide or vane to outside the valve guide or valve axis. Flow under the steep angled sloped portion 63 to the inside of the valve guide or valve axis, instead, requires a light change or offset in the flow direction. This compensates for the effect of the bevel angle difference, further slowing the flow along the inside of the valve axis to a lesser extent along the inside of the valve axis than at the outside of the valve axis, further enhancing the port's ability to generate vortices.

In the particular example of the inlet port configuration shown, the port inlet 40 has a height above the throat 39 that is approximately twice the diameter of the valve head 48. The central passage slopes downward at an angle of approximately 30-45 °. The sloped portions 62, 63 are located at a fairly steep angle of 30-60 ° with respect to the plane of the cylinder head lower wall 26. The angle of the inner beveled portion 63 preferably exceeds the angle of the outer beveled portion 62 by about 10 ° or more.

In the vortex chamber, its diameter is somewhat larger than the diameter of the port throat, and the height from the throat 39 or valve seat 38 to the shelf 64 is the same as the diameter of the valve head 48. The flow regions on either side of the valve guide are divided approximately evenly by the valve guide boss and the guide vanes. Further, the shelf area is about 40 to 50 of the vortex chamber area on a horizontal plane parallel to the cylinder head bottom wall 26.
%be equivalent to.

In a flow box test comparing the port according to the present invention to a vortexless open port or a regular spiral vortex port, the present invention exhibits superior vortex and flow characteristics over the prior art over a significant portion of the flow range. It was Some of the features that may be important in achieving this result are an enlarged vortex chamber part partially covered by a flat shelf above the port throat,
There are tethered slopes with different angles of inclination, these features alter the flow of fresh air through both sides of the valve stem, directing this flow to different angles and into the vortex chamber section 66. Creates a fairly large vortex and throats it
39 through to the combustion chamber.

Thus, in the present invention, the sloped portions 62, 63 of different angles to the upper wall 55 on both sides of the valve stem 49 direct the inlet gas flow downward, and the steep sloped portion 63 slows the flow inside the port. However, at the sloped portion 62 having a gentle angle, a fast flow having a larger tangential direction to the cylinder wall is given. This creates a vortex in the inlet gas flow. The flat ledge 64 and vortex chamber 66 beyond the valve stem keeps the port open to unthrottled gas flow, increasing full throttle flow efficiency.

[Brief description of drawings]

FIG. 1 is a fragmentary bottom view of a cylinder head of an internal combustion engine having an intake port according to the present invention, as seen from the plane indicated by line 1-1 in FIG. FIG. 2 is a cross-sectional view of the internal combustion engine passing through the cylinder head intake port, and is a view showing a slope lower than the plane indicated by line 2-2 in FIG. FIG. 3 is a transverse sectional view of the internal combustion engine passing through the cylinder head intake port, and is a view showing a slope higher than the plane indicated by line 3-3 in FIG. 4 is a cross-sectional view through the cylinder head of FIG. 1 as seen from the plane indicated by line 4-4 in FIG. FIG. 5 is a side view of the core for forming the intake port according to the present invention, viewed from the plane shown by line 5-5 in FIG. FIG. 6 is a top view of the core of FIG. FIG. 7 is a perspective view of the core shown in FIG. In the drawing, 10 ... internal combustion engine, 11 ... cylinder block, 12 ... cylinder, 14 ... piston, 15 ... connecting rod,
16 …… Cylinder head, 27 …… Combustion chamber recess, 28 …… Combustion chamber, 30 …… Spark plug, 31 …… Exhaust port, 32 …… Intake port, 34 …… Valve seat, 35 …… Throat, 36… … Exhaust port, 38
...... Valve seat, 39 ...... Throat part, 40 ...... Intake port, 41 ...... Intake valve, 42 ...... Exhaust valve, 43 ...... Head, 47 ...... Spring, 48 ...
… Head, 51 …… Valve guide, 52,54 …… Valve guide boss, 60…
… Guide vanes, 62, 63 …… Slope, 64 …… Shelf, 66…
... whirlpool

Claims (8)

[Claims] 1. A cylinder (12) having an axis closed at one end (19), an intake passage (32) communicating with the cylinder (12) through the closed end (19), and a poppet intake valve. (41), the intake valve includes a stem (49) and a head (48), and further has a valve axis (50) so that the intake valve can reciprocate along the valve axis (50). Intake passage (3
2) located in the cylinder (1) of the intake passage (32)
2) Internal combustion engine adapted to control communication with (1
0), the intake passage (32) has the cylinder (12)
A throat (39) of generally circular cross section that is open to the inside and is closed by the intake valve (41) and is separated from this throat (39) and offset from the valve axis (50). An inlet section (40) and extending from and around the valve axis (50) from the inlet section (40),
And a fluid passage extending to the bottom of the valve head (48) when opened to the throat (39), the fluid passage including the first and second sloped portions (62, 63). 55) and a shelf portion (64) which is located opposite to the throat (39) and is opposed to the throat (39), and the inclined surface portions (62, 63) are inclined downward so that the valve axis (50) is formed. On the other hand, it is connected to the shelf part (64) on almost the opposite side, and the sloped parts (62, 63) are located at a steep angle with respect to the shelf part (64), and one of the sloped parts (63) is the other. Has a much steeper angle than the slope (62) of the
The flow of fluid through 3) is slower and more downwardly directed than the flow of fluid at a slower downward angle and higher velocity through the other beveled portion (62), thereby causing a gentle sloped sloped portion ( An internal combustion engine of a spark ignition type, characterized in that a fluid flow for vortex generation is preferentially introduced into a region of a shelf portion (64) from below 62). 2. The internal combustion engine according to claim 1, wherein the fluid flow passage includes a valve guide boss (54) surrounding the valve axis (50) and partially protruding into the flow passage. , The shelf portion (64) extends from the vicinity of the end of the valve guide boss (54) so as to face the throat (39) at a substantially distance from each other, and the beveled surface portions (62, 63) have the slope portion (62, 63). ) An internal combustion engine characterized by being connected to a shelf part (64) in the vicinity. 3. The internal combustion engine according to claim 2, wherein the intake passage has a sloped flow along a side of the valve axis (50) below a steep sloped portion (63). It makes a greater angle with the flow in the intake passage (32) immediately upstream of the valve guide boss (54) than if it were below the gentle slope (62) and along the opposite side of the valve axis (50). The large angle is measured in a plane perpendicular to the valve axis (50), so that the fluid flows preferentially from the opposite side of the valve axis (50) to the shelf area. An internal combustion engine characterized by the above. 4. The internal combustion engine according to claim 3, wherein the valve guide boss (54) is tangential to both sides of the valve guide boss (54) at an upstream edge (61). A guide vane (60) having two intersecting faces (61a, 61b) is included, and one face (61b) of these faces is the valve axis (50).
Of the intake passageway (32) immediately upstream of the guide vanes (60), the surface (61b) being combined with the fluid flow along the opposite side of the flow path and positioned substantially parallel to the flow.
Is almost aligned with the flow of the fluid inside, and the other surface (61a)
Is located at a substantial angle to the fluid flow. 5. A cylinder (12) having an axis and a cylinder head (1) closing one end (19) of the cylinder (12).
6) and an intake passage (32) that penetrates the cylinder head (16) and communicates with the cylinder (12) through the closed end (19), and is offset to one side of the cylinder axis by the intake passage (32). 32) is arranged in the intake passage (32) so as to reciprocate so as to control communication with the cylinder (12).
In an internal combustion engine including a poppet intake valve (41) having a central axis (50), the intake passage has the valve axis (5).
The intake valve (41) opens and closes the throat (39) including a throat (39) having a substantially circular cross section, which is open in the cylinder (12) near one side of the throat (0). And the intake passage has a throat (3
9) and an inlet portion (40) that is offset from the valve axis (50) and from this inlet portion (40) to the valve axis (5
0) including a fluid flow path extending to both sides of the cylinder to the throat (39), the flow path around the valve axis (50) being adjacent to the cylinder axis to the inner flow path and the side portion of the cylinder (12). A valve guide boss (54) which is divided into an adjacent outer flow path, the fluid flow path surrounds the valve axis (50), and partially protrudes into the flow path between the inner and outer flow paths; The top wall (5) including the first and second slope portions (62, 63) and the shelf portion (64)
5) and the shelf portion (64) extends from the vicinity of the end of the valve guide boss (54) so as to face the throat (39) substantially at a distance, and the slope portion (62, 6).
3) is connected to the shelf part (64) near the valve guide boss (54), and the sloped parts (62, 63) are almost opposite to the valve guide boss (54), and to the shelf part (64). It is inclined downward at a steep angle, one of the slopes (63) constitutes the wall surface of the inner flow path, and has a much steeper angle than the other slope (62). A loose downward angle in the outer channel partially defined by the beveled portion (62) that slows the flow in the inner channel relative to higher velocity fluid flow and directs it more rapidly downward. The spark-ignition internal combustion engine is characterized in that the swirl-generating fluid flow is preferentially introduced into the area of the shelf portion (64) from below the gently inclined sloped portion (62). 6. The internal combustion engine according to claim 5, wherein the intake passage (32) makes the flow in the outer flow passage substantially tangential to the side portion of the cylinder. Forming a considerably larger angle with the flow direction of the fluid in the intake passage (32) immediately upstream of the valve guide boss (54) than when the flow direction of the inner flow path is the flow direction of the outer flow path, An internal combustion engine, characterized in that a large angle is measured in a plane perpendicular to the cylinder axis, and more fluid is preferentially caused to flow from the outer flow passage to the shelf region. 7. The internal combustion engine according to claim 6, wherein the shelf portion (64) is located in a plane substantially perpendicular to the cylinder axis. 8. The internal combustion engine according to claim 7, wherein the valve guide boss (54) is tangential to both sides of the valve guide boss (54) and intersects at two faces (61) on the upstream side (61). 61a, 61b) having a guide vane (60), one of these faces (61b) forming a part of the outer flow passage, and the intake passage (32) immediately upstream of the guide vane. The internal combustion engine, which is substantially aligned with the flow direction in the inside, and the other surface (61a) is positioned at a considerable angle with respect to the upstream fluid flow.